1. Technical Field
The present invention relates to a method of and system for monitoring the conditions of the internal environment of a container utilizing multiple sensors and, more particularly, but not by way of limitation, to a method of and system for utilizing multiple sensors for monitoring the conditions of the internal environment of intermodal freight containers throughout a supply chain.
2. History of the Related Art
The vast majority of goods shipped throughout the world are shipped via what are referred to as intermodal freight containers. As used herein, the term “containers” includes any container (whether with wheels attached or not) that is not transparent to radio frequency signals, including, but not limited to, intermodal freight containers. The most common intermodal freight containers are known as International Standards Organization (ISO) dry intermodal containers, meaning they meet certain specific dimensional, mechanical and other standards issued by the ISO to facilitate global trade by encouraging development and use of compatible standardized containers, handling equipment, ocean-going vessels, railroad equipment and over-the-road equipment throughout the world for all modes of surface transportation of goods. There are currently more than 12 million such containers in active circulation around the world as well as many more specialized containers such as refrigerated containers that carry perishable commodities. The United States alone receives approximately six million loaded containers per year, or approximately 17,000 per day, representing nearly half of the total value of all goods received each year.
Since approximately 90% of all goods shipped internationally are moved in containers, container transport has become the backbone of the world economy.
The sheer volume of containers transported worldwide renders individual physical inspection impracticable, and only approximately 2% to 3% of containers entering the United States are actually physically inspected. Risk of introduction of a terrorist biological, radiological or explosive device via a freight container is high, and the consequences to the international economy of such an event could be catastrophic, given the importance of containers in world commerce.
Even if sufficient resources were devoted in an effort to conduct physical inspections of all containers, such an undertaking would result in serious economic consequences. The time delay alone could, for example, cause the shut down of factories and undesirable and expensive delays in shipments of goods to customers.
Current container designs fail to provide adequate mechanisms for establishing and monitoring the security of the containers or their contents. A typical container includes one or more door hasp mechanisms that allow for the insertion of a plastic or metal indicative “seal” or bolt barrier conventional “seal” to secure the doors of the container.
The door hasp mechanisms that are conventionally used are very easy to defeat, for example, by drilling an attachment bolt of the hasp out of a door to which the hasp is attached. The conventional seals themselves currently in use are also quite simple to defeat by use of a common cutting tool and replacement with a rather easily duplicated seal.
A more advanced solution proposed in recent time is an electronic seal (“e-seal”). These e-seals are equivalent to traditional door seals and are applied to the containers via the same, albeit weak, door hasp mechanism as an accessory to the container, but include an electronic device such as a radio or radio reflective device that can transmit the e-seal's serial number and a signal if the e-seal is cut or broken after it is installed. However, the e-seal is not able to communicate with the interior or contents of the container and does not transmit information related to the interior or contents of the container to another device.
The e-seals typically employ either low power radio transceivers or use radio frequency backscatter techniques to convey information from an e-seal tag to a reader installed at, for example, a terminal gate. Radio frequency backscatter involves use of a relatively expensive, narrow band high-power radio technology based on combined radar and radio-broadcast technology. Radio backscatter technologies require that a reader send a radio signal with relatively high transmitter power (i.e., 0.5-3 W) that is reflected or scattered back to the reader with modulated or encoded data from the e-seal.
In addition, e-seal applications currently use completely open, unencrypted and insecure air interfaces and protocols allowing for relatively easy hacking and counterfeiting of e-seals. Current e-seals also operate only on locally authorized frequency bands below 1 GHz, rendering them impractical to implement in global commerce involving intermodal containers since national radio regulations around the world currently do not allow their use in many countries.
Furthermore, the e-seals are not effective at monitoring security of the containers from the standpoint of alternative forms of intrusion or concern about the contents of a container, since a container may be breached or pose a hazard in a variety of ways since the only conventional means of accessing the inside of the container is through the doors of the container. For example, a biological agent could be implanted in the container through the container's standard air vents, or the side walls of the container could be cut through to provide access. Although conventional seals and the e-seals afford one form of security monitoring the door of the container, both are susceptible to damage. The conventional seal and e-seals typically merely hang on the door hasp of the container, where they are exposed to physical damage during container handling such as ship loading and unloading. Moreover, conventional seals and e-seals cannot monitor the contents of the container.
The utilization of multiple sensors for monitoring the interior of a container could be necessary to cover the myriad of possible problems and/or threatening conditions. For example, the container could be used to ship dangerous, radio-active materials, such as a bomb. In that scenario, a radiation sensor would be needed in order to detect the presence of such a serious threat. Unfortunately, terrorist menaces are not limited to a single category of threat. Both chemical and biological warfare have been used and pose serious threats to the public at large. For this reason, both types of detectors could be necessary, and in certain situations, radiation, gas and biological sensors could be deemed appropriate. One problem with the utilization of such sensors is, however, the transmission of such sensed data to the outside world when the sensors are placed in the interior of the container. Since standard intermodal containers are manufactured from steel that is opaque to radio signals, it is virtually impossible to have a reliable system for transmitting data from sensors placed entirely within such a container unless the data transmission is addressed. If data can be effectively transmitted from sensors disposed entirely within an intermodal container, conditions such as temperature, light, combustible gas, proteins (biometric sensors) motion, radio activity, biological and other conditions and/or safety parameters can be monitored. Moreover, the integrity of the mounting of such sensors are critical and require a more sophisticated monitoring system than the aforementioned door hasp mechanisms that allow for the insertion of a plastic or metal indicative “seal” or bolt barrier conventional “seal” to secure the doors of the container.
In addition to the above, the monitoring of the integrity of containers via door movement can be relatively complex. Although the containers are constructed to be structurally sound and carry heavy loads, both within the individual containers as well as by virtue of containers stacked upon one another, each container is also designed to accommodate transverse loading to accommodate dynamic stresses and movement inherent in (especially) ocean transportation and which are typically encountered during shipment of the container. Current ISO standards for a typical container may allow movement on a vertical axis due to transversal loads by as much as 40 millimeters relative to one another. Therefore, security approaches based upon maintaining a tight interrelationship between the physical interface between two container doors are generally not practicable.
It would therefore be advantageous to provide a method of and system for both monitoring the movement of the doors of a container relative to the container structure in a cost effective, always available, yet reliable fashion as well as providing for a data path or gateway for multiple sensors placed in a container to detect alternative means of intrusion or presence of dangerous or illicit contents to receivers in the outside world.